01 / 10TED-Ed≈ approximate level B21:19–1:27 , , , , .
02 / 10The New Yorker≈ approximate level B10:50–0:57
, .
03 / 10TED≈ approximate level C13:52–4:02
, ’s .
04 / 10CrashCourse≈ approximate level C12:45–2:53
.
05 / 10CNBC Make It≈ approximate level B24:05–4:12
, .
06 / 10CrashCourse≈ approximate level A210:45–10:50
’s .
07 / 10The Economist≈ approximate level B13:47–3:53
.
08 / 10BBC Ideas≈ approximate level C11:46–1:57
, , .
09 / 10TED-Ed≈ approximate level C11:45–2:00
, , , .
10 / 10Lex Clips≈ approximate level B12:01–2:14
, , .